CommonUI Back button no longer works when Get Desired Focus Target override is used

I have implemented Commoniu, and everything seems to be working flawlessly…except one smaaaaaallll detail that I can’t figure out. If I override the desired focus target on activation (or even just set focus to a button that I want the controller to fixate on), the back button no longer works. It only works when I activate the widget with no focus target. Any ideas?